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1// SPDX-License-Identifier: GPL-2.02/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */3#include "vmlinux.h"4#include <bpf/bpf_helpers.h>5#include <bpf/bpf_tracing.h>6#include <bpf/bpf_core_read.h>7#include "bpf_misc.h"8 9char _license[] SEC("license") = "GPL";10 11static long stack[256];12 13/*14 * KPROBE contexts15 */16 17__weak int kprobe_typedef_ctx_subprog(bpf_user_pt_regs_t *ctx)18{19 return bpf_get_stack(ctx, &stack, sizeof(stack), 0);20}21 22SEC("?kprobe")23__success24int kprobe_typedef_ctx(void *ctx)25{26 return kprobe_typedef_ctx_subprog(ctx);27}28 29/* s390x defines:30 *31 * typedef user_pt_regs bpf_user_pt_regs_t;32 * typedef struct { ... } user_pt_regs;33 *34 * And so "canonical" underlying struct type is anonymous.35 * So on s390x only valid ways to have PTR_TO_CTX argument in global subprogs36 * are:37 * - bpf_user_pt_regs_t *ctx (typedef);38 * - struct bpf_user_pt_regs_t *ctx (backwards compatible struct hack);39 * - void *ctx __arg_ctx (arg:ctx tag)40 *41 * Other architectures also allow using underlying struct types (e.g.,42 * `struct pt_regs *ctx` for x86-64)43 */44#ifndef bpf_target_s39045 46#define pt_regs_struct_t typeof(*(__PT_REGS_CAST((struct pt_regs *)NULL)))47 48__weak int kprobe_struct_ctx_subprog(pt_regs_struct_t *ctx)49{50 return bpf_get_stack((void *)ctx, &stack, sizeof(stack), 0);51}52 53SEC("?kprobe")54__success55int kprobe_resolved_ctx(void *ctx)56{57 return kprobe_struct_ctx_subprog(ctx);58}59 60#endif61 62/* this is current hack to make this work on old kernels */63struct bpf_user_pt_regs_t {};64 65__weak int kprobe_workaround_ctx_subprog(struct bpf_user_pt_regs_t *ctx)66{67 return bpf_get_stack(ctx, &stack, sizeof(stack), 0);68}69 70SEC("?kprobe")71__success72int kprobe_workaround_ctx(void *ctx)73{74 return kprobe_workaround_ctx_subprog(ctx);75}76 77/*78 * RAW_TRACEPOINT contexts79 */80 81__weak int raw_tp_ctx_subprog(struct bpf_raw_tracepoint_args *ctx)82{83 return bpf_get_stack(ctx, &stack, sizeof(stack), 0);84}85 86SEC("?raw_tp")87__success88int raw_tp_ctx(void *ctx)89{90 return raw_tp_ctx_subprog(ctx);91}92 93/*94 * RAW_TRACEPOINT_WRITABLE contexts95 */96 97__weak int raw_tp_writable_ctx_subprog(struct bpf_raw_tracepoint_args *ctx)98{99 return bpf_get_stack(ctx, &stack, sizeof(stack), 0);100}101 102SEC("?raw_tp")103__success104int raw_tp_writable_ctx(void *ctx)105{106 return raw_tp_writable_ctx_subprog(ctx);107}108 109/*110 * PERF_EVENT contexts111 */112 113__weak int perf_event_ctx_subprog(struct bpf_perf_event_data *ctx)114{115 return bpf_get_stack(ctx, &stack, sizeof(stack), 0);116}117 118SEC("?perf_event")119__success120int perf_event_ctx(void *ctx)121{122 return perf_event_ctx_subprog(ctx);123}124 125/* this global subprog can be now called from many types of entry progs, each126 * with different context type127 */128__weak int subprog_ctx_tag(void *ctx __arg_ctx)129{130 return bpf_get_stack(ctx, stack, sizeof(stack), 0);131}132 133struct my_struct { int x; };134 135__weak int subprog_multi_ctx_tags(void *ctx1 __arg_ctx,136 struct my_struct *mem,137 void *ctx2 __arg_ctx)138{139 if (!mem)140 return 0;141 142 return bpf_get_stack(ctx1, stack, sizeof(stack), 0) +143 mem->x +144 bpf_get_stack(ctx2, stack, sizeof(stack), 0);145}146 147SEC("?raw_tp")148__success __log_level(2)149int arg_tag_ctx_raw_tp(void *ctx)150{151 struct my_struct x = { .x = 123 };152 153 return subprog_ctx_tag(ctx) + subprog_multi_ctx_tags(ctx, &x, ctx);154}155 156SEC("?perf_event")157__success __log_level(2)158int arg_tag_ctx_perf(void *ctx)159{160 struct my_struct x = { .x = 123 };161 162 return subprog_ctx_tag(ctx) + subprog_multi_ctx_tags(ctx, &x, ctx);163}164 165SEC("?kprobe")166__success __log_level(2)167int arg_tag_ctx_kprobe(void *ctx)168{169 struct my_struct x = { .x = 123 };170 171 return subprog_ctx_tag(ctx) + subprog_multi_ctx_tags(ctx, &x, ctx);172}173